The present invention is directed toward the field of connecting one or more local terminals to remote host systems over a packet-switched network, and then managing the established connections. In particular, a system and method for managing packet-switched connections between one or more point-of-sale terminals and remote transaction processing host systems (such as credit-card authorization systems) through a gateway is disclosed. The system and method are particularly useful in a wireless packet-switched environment, but can be extended to any type of packet-switched network. The gateway forms a bridge between the point-of-sale terminals, which are connected to the gateway via a packet-switched network, such as a wireless network, and at least one transaction processing host connected to the gateway via a land-line network, such as an X.25 synchronous data network. Although the present invention is describe in terms of point-of-sale transaction processing, its teaching is not limited to this one application and can be used in any type of transaction processing environment where multiple connections are established, such as data base inquiry, message sending and acknowledgment, on-line transaction processing and order placement, intelligent forms/agents, dispatch systems, or wireless telemetry, to name a few.
Recently, customers at point-of-sale locations have been making purchases by means other than cash, like a credit card. The credit card information is input into a local terminal by swiping the credit card through a credit card reader or by entering the credit card data manually into a local terminal. Before the purchase can be completed, the transaction must be validated by performing a credit check on the card and the amount of the purchase. Generally this requires communication between the local terminal at the point-of-sale location and a remote host system that authorizes the transaction, the remote host system storing information regarding the validity and credit limits of various consumer credit cards.
Prior to the availability of wireless packet-switched networks, such as the Mobitex Radio Network ("Mobitex"), which is operated by RAM Mobile Data, or DataTAC, which is operated by Ardis, credit card authorizations were performed almost exclusively via the Public Switched Telephone Network ("PSTN"). In this type of prior art transaction processing system each point-of-sale terminal was connected to a PSTN telephone line, and created a circuit-switched connection to the host transaction processing system. Also common was the use of a PSTN PAD (Packet Assembler Disassembler) for multiplexing all the connections through an X.25 network to a host. Once connected, the point-of-sale terminal communicated directly to the host system in order to obtain authorization for the particular transaction.
With the coming of wireless packet-switched networks, such as those mentioned above, several advantages were available for connecting point-of-sale terminals to remote host systems. For example, the point-of-sale terminals no longer had to be directly connected to a single telephone connection, so multiple terminals at the point-of-sale location could share a single wireless connection, which was more efficient, less costly, and provided faster response times than the land-line PSTN terminals. This method of sharing the wireless connection was accomplished by "packetizing" the data from each wireless terminal and embedding certain network header information into each packet to identify the sending and receiving systems and facilitate routing of the packets through the wireless network. Such wireless terminals could communicate over a land-line phone connection or a wireless packet-switched network. An example of such a wireless point-of-sale terminal capable of dual-mode communication is disclosed in U.S. Pat. No. 5,444,763, assigned to the assignee of the present invention. The teaching provided by this patent is hereby incorporated by reference.
Prior attempts to connect point-of-sale terminals to remote transaction processing hosts via a wireless packet-switched network included an intermediate gateway computer. The gateway had at least two communication ports, one connected to the wireless network, and a second port connected to a land-line network compatible with the remote transaction host. An example of such a gateway system is disclosed in U.S. Pat. No. 5,559,800, which is assigned to the assignee of the present invention. The disclosure of this patent is hereby incorporated by reference. Using the prior method, the point-of-sale terminal transmitted a packet of information over the wireless network to the gateway to initiate a connection to a remote host. The gateway automatically created a direct connection to the host transaction processing computer and then forwarded the information in the packet to the host system. The direct connection was terminated when the host system responded to the request packet. In this type of system, the gateway's functionality was limited to receiving, transforming and communicating messages between the point-of-sale terminals and the host transaction processing system.
One disadvantage of this prior method of wireless transaction processing was that the host system required special modification to support the packetized communication from the gateway computer. The host systems used a legacy protocol that was not compatible with the more recent packet-switched scheme employed by the wireless networks. Legacy protocols were unfriendly to wireless networks because of short time exchange requirements and "chatty" inefficient conversations. Another disadvantage of this early method was that there was no way to distinguish one transaction packet from another. This lack of transaction identification could cause communication problems with the host system when, for example, a packet was lost in the wireless network or a request sequence was aborted, leading to a point-of-sale terminal receiving an authorization response from a previously aborted request--referred to herein as "rogue" packet responses. Yet another disadvantage of this prior method was that the gateway and its associated communication protocol software had to be customized for every host processing system.
Another prior method of wireless transaction processing provided a fully simulated, i.e. virtual, circuit-switched connection over the wireless packet network between the local point-of-sale terminal(s) and the remote transaction processing host. This method provided some advantages over the actual circuit-switched connection noted above, but was disadvantageous because it required numerous packets to be sent over the wireless network in order to establish and tear down the virtual connection. This decreased the efficiency and speed of the transaction connection and increased costs for wireless networks that charge on a per-packet-sent basis.
Therefore, there remains a need in this art for a system and method for efficient and reliable management of connections over a packet data network, such as a wireless packet network. More particularly, there remains a need for such a system and method that manages connections between one or more point-of-sale terminals and remote transaction processing hosts through a gateway computer.
There remains a further need for such a system and method that overcomes the disadvantages of the prior connection systems by providing a means for identifying particular transaction requests generated by each point-of-sale terminal, and a means for synchronizing the point-of-sale terminals and the gateway computer so that the gateway can determine whether a particular transaction has been aborted, or a packet has been lost during transmission, thereby avoiding the problem of authorizing aborted requests.
There remains an additional need for such a system and method that minimizes communication over the packet-switched network by providing enhanced processing capability at the gateway computer that allows the gateway to manage communication with the remote host processing system.